Ch 8 Quant. in Chem RXNs/Stoichiometry STUDY GUIDE Accelerated Chemistry

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1 Ch 8 Quant. in Chem RXNs/Stoichiometry STUDY GUIDE Accelerated Chemistry Name /108 TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. Correct the False statments by changing the underlined word(s). 1) Given the recipe: 2 cups flour + 1 egg + 3 oz blueberries 4 muffins. You can make 1 dozen muffins from 3 eggs. 1) 2) Given the chemical equation: 2 Ca + O2 2 CaO, if 2 moles of CaO are formed in this reaction, then 2 moles of O2 must have reacted. 2) 3) The limiting reactant determines what the actual yield is. 3) 4) The limiting reagent is the product that is completely consumed in a chemical reaction. 4) 5) Given the reaction: 2 Na(s) + Cl2(g) 2 NaCl(s) The conversion factor for chlorine gas to sodium chloride is: 1 mol Cl2 2 mol NaCl 5) 6) Before determining conversion factors, it is necessary to make sure the equation is properly balanced. 6) 7) The conversion factor between mass and moles for a compound is the molar mass. 7) 8) The actual yield is the same as the theoretical yield if the reaction goes to completion and there is no loss of product. 8) 9) Thermal energy flows into the reaction and out of the surroundings in an endothermic reaction. 9) 10) The conversion factor for moles of carbon dioxide to mass of carbon dioxide is: 1 mole CO g 10) 11) The limiting reactant is the reactant that produces the maximum amount of product. 11) 12) Given the reaction: 2 Na(s) + Cl2(g) 2 NaCl(s) The conversion factor for chlorine gas to sodium metal is: 2 mol Cl 2 mol Na 12) 13) One of the advantages of burning fossil fuels is that it produces O2 for humans to breathe. 13) 14) For the following reaction you have 8 grams of hydrogen and 2 grams of oxygen. 14) 2H2 + O2 2H2O The limiting reagent is the oxygen. 15) If the theoretical yield of a reaction is 144 grams and the actual yield of the reaction is 72 grams, the percent yield of the reaction is 200%. 15) 1

2 16) For the following reaction you have 8 grams of hydrogen and 2 grams of oxygen. 16) 2H2 + O2 2H2O The excess reactant is the oxygen. 17) The percent yield can never be greater than 100%. 17) 18) The limiting reactant is not necessarily the reactant with the least mass. 18) 19) For the following reaction you have 8 grams of hydrogen and 2 grams of oxygen. 19) 2H2 + O2 2H2O The theoretical yield of the reaction is 4 grams of water. 20) The percent yield is calculated by dividing the actual yield by the theoretical yield times ) 21) The theoretical yield is the amount of each reactant needed in order to make the maximum amount of product. 21) 22) The actual yield is the amount of product actually produced by a chemical reaction. 22) 23) An exothermic reaction has a negative enthalpy of reaction. 23) 24) Given the following generic equation, 2 A + 3B A2B3 H rxn = +444 kj, if you completely reacted 1 mole of compound A, the amount of heat absorbed would be 222 kj. 24) 25) When viewing a chemical equation, the limiting reactant can never be a chemical on the product side of the equation. 25) 26) Given the recipe: 2 cups flour + 1 egg + 3 oz blueberries 4 muffins If you have 5 cups of flour, 3 eggs and plenty of blueberries, the limiting reactant is the eggs. 26) 27) The enthalpy of reaction, H rxn, is the amount of thermal energy that flows when a reaction occurs at constant temperature. 27) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 28) The average global temperature depends on all factors EXCEPT what? 28) A) the amount of outgoing heat lost to space B) the amount of greenhouse gases C) the amount of incoming sunlight D) the angle of the earth's surface in relation to the incoming sunlight 29) Which of the below statements about global warming is FALSE? 29) A) Greenhouse gases prevent heat from leaving the earth. B) Greenhouse gases allow sunlight to reach and heat the earth. C) Some greenhouses gases are needed to keep the proper temperature balance. D) If the level of greenhouse gases increases, the temperature will decrease. 2

3 30) The primary cause of increasing greenhouse gases is: 30) A) the burning of vast amounts of rain forests. B) the production of CO 2 by respiration. C) the release of CO 2 by decreasing solubility in the ocean. D) the increased use of natural gas, petroleum and coal. 31) Which of the following is TRUE? 31) A) Stoichiometry allows prediction of how much of the reactants are necessary to form a given amount of product. B) Stoichiometry allows prediction of the amounts of products that form in a chemical reaction based on the amounts of reactants. C) Stoichiometry shows the numerical relationship between chemical quantities in a balanced chemical equation. D) All of the above are true. 32) How many waffles can be made from 1 dozen eggs, assuming you have enough of all other ingredients? A) 12 B) 48 C) 4 D) 16 32) 33) How many eggs are needed to make 1 dozen waffles, assuming you have enough of all other ingredients? A) 9 B) 48 C) 12 D) 16 33) 34) How many moles of water are made from complete reaction of 2.2 moles of oxygen gas with hydrogen gas? Given the reaction: 2H2 + O2 2H2O A) 1.1 B) 4.4 C) 2.2 D) ) 35) How many moles of water are made from complete reaction of 1.4 moles of hydrogen gas? Given the reaction: 2H2 + O2 2H2O A) 1.4 B) 2.8 C) 0.7 D) ) 36) How many moles of H2 can be made from complete reaction of 3.0 moles of Al? Given: 2 Al + 6 HCl 2 AlCl3 + 3 H2 A) 3.0 moles B) 4.5 moles C) 3 moles D) 9.0 moles 36) 37) How many moles of aluminum are needed to make 9 moles of molecular hydrogen? Given the reaction: 2 Al + 6 HCl 2 AlCl3 + 3H2 A) 3 moles B) 4 moles C) 6 moles D) 2 moles 37) 38) How many moles of chlorine gas are needed to make 0.6 moles of sodium chloride? Given the reaction: 2Na + Cl 2 2NaCl A) 3.6 B) 0.6 C) 1.2 D) ) 3

4 39) How many moles of sodium metal are needed to make 3.6 moles of sodium chloride? Given the reaction: 2Na + Cl 2 2NaCl A) 1.8 B) 3.6 C) 7.2 D) ) 40) Suppose two chemical reactions are linked together in a way that the O2 produced in the first reaction goes on to react completely with Mg to form MgO in the second reaction. Reaction one: 2 KClO3 3 O2 + 2 KCl Reaction two: 2 Mg + O2 2 MgO If you start with 4 moles of KClO3, how many moles of MgO could eventually form? A) 4 moles B) 6 moles C) 12 moles D) 2 moles 40) 41) Given the balanced equation CH4 + 2 O2 CO2 + 2 H2O, which of the following is NOT a correct conversion factor? A) 2 mole H2O = g B) 1 mole CH4 2 mole H2O C) 2 mole O2 1 mole CO2 D) 1 mole O2 = g 41) 42) How many grams of water are made from the reaction of 4.0 grams of hydrogen gas? Given the reaction: 2H 2 + O 2 2H 2 O A) 36 B) 4.5 C) 72 D) 18 42) 43) How many grams of water are made from the reaction of 16.0 grams of oxygen gas? Given the reaction: 2H 2 + O 2 2H 2 O A) 18 B) 16 C) 9 D) 36 E) not enough information 43) 44) How many grams of chlorine gas are needed to make 117 grams of sodium chloride? Given the reaction: 2Na + Cl 2 2NaCl A) 48.2 B) 35.5 C) 142 D) ) 45) How many grams of sodium metal are needed to make 29.3 grams of sodium chloride? Given the reaction: 2Na + Cl 2 2NaCl A) 23.0 B) 5.75 C) 11.5 D) ) 46) Given that 4 NH O 2 4 NO + 6 H 2 O, when 4.50 mol of H 2 O are formed, the amount of NO formed is A) 3.00 mol. B) 6.75 mol. C) 1.50 mol. D) 4.50 mol. 46) 47) Given that 4 NH O 2 4 NO + 6 H 2 O, if 3.00 mol NH 3 were made to react with excess of oxygen gas, the amount of H 2 O formed would be A) 3.00 mol. B) 4.50 mol. C) 6.00 mol. D) 2.00 mol. 47) 4

5 48) Iron metal reacts with oxygen to produce iron(iii) oxide. If you have 12.0 moles of iron for complete reaction, you need A) 9.0 moles of O 2 and produce 6.0 moles of Fe 2 O 3. B) 4.5 moles of O 2 and produce 3.0 moles of Fe 2 O 3. C) 9.0 moles of O 2 and produce 3.0 moles of Fe 2 O 3. D) 12.0 moles of O 2 and produce 24.0 moles of Fe 2 O 3. 48) 49) Many metals react with halogens to give metal halides. For example, 2 Al (s) + 3 Cl 2 (g) 2 AlCl 3 (s) If you begin with 13.5 g of aluminum, A) you will need 26.6 g Cl 2 for complete reaction and will produce 49.0 g of AlCl 3. B) you will need 53.2 g Cl 2 for complete reaction and will produce 66.7 g of AlCl 3. C) you will need 11.8 g Cl 2 for complete reaction and will produce 49.0 g of AlCl 3. D) you will need 23.6 g Cl 2 for complete reaction and will produce 66.7 g of AlCl 3. 49) 50) A chemist wishes to perform the following reaction: N2 + 3 H2 2 NH3 If only 14.0 g of N2 is available, what is the minimum amount, in grams, of H2 needed to completely react with this quantity of N2? A) 1.01 g B) 3.03 g C) 6.06 g D) 1.51 g 50) 51) Which of the following statements is FALSE? 51) A) The theoretical yield is the amount of product that can be made based on the amount of limiting reagent. B) The actual yield is the amount of product actually produced by a chemical reaction. C) The limiting reactant is completely consumed in a chemical reaction. D) All of the above are true statements. 52) Which ingredient is the limiting reactant if you have 5 cups of flour, 9 eggs and 3 tbs of oil? A) waffles B) eggs C) oil D) flour 52) 53) What is the theoretical yield of waffles if you have 5 cups of flour, 9 eggs and 3 tbs of oil? A) 12 B) 4 C) 6 D) 10 53) 54) Which ingredient is the limiting reactant if you have 6 cups of flour, 9 eggs and 2 tbs of oil? A) eggs B) flour C) waffles D) oil 54) 55) A tricycle factory uses the following items to produce one tricycle: 3 tires, 1 frame, and 2 pedals. If the factory has available 270 tires, 90 frames, and 170 pedals, which item would limit the amount of complete tricycles that can be assembled. A) tires B) pedals C) frames D) both tires and frames are limiting 55) 5

6 56) What is the theoretical yield of waffles if you have 6 cups of flour, 9 eggs and 2 tbs of oil? A) 12 B) 10 C) 8 D) 4 56) 57) Consider the following generic chemical equation: 2A + 5B C + 3D If you react 4 units of A with 10 units of B, which statement is TRUE? A) Substance B will be the limiting reactant. B) There is just enough of A and B so that everything reacts completely. C) Substance A will be the limiting reactant. D) Substance C cannot be formed from this reaction. 57) 58) Consider the following generic chemical equation: 2W + 3X 3Y + Z When 5 units of W and 6 units of X are allowed to react, the limiting reactant would be: A) Z B) W C) X D) Y 58) 59) Determine the theoretical yield of C when 3 units of A and 10 units of B are reacted in the following generic chemical equation: 2A + 5B 4C. A) 4 B) 6 C) 3 D) 8 59) 60) Given the balanced equation CO2 + Si SiO2 + C, if you were to react 1 mole of CO2 with 1 mole of Si, which statement is TRUE? A) The Si is the limiting reactant. B) You have equal stoichiometric amounts of reactants. C) The CO2 is the limiting reactant. D) The SiO2 is the limiting reactant. 60) 61) If the theoretical yield of a reaction is 42.0 grams of product and the percent yield is 75%. How many grams were actually produced? A) 56 B) 5400 C) 32 D) ) 62) The theoretical yield of a reaction is 75.0 grams of product and the actual yield is 42.0g. What is the percent yield? A) 178 B) 56.0 C) 75.0 D) ) 63) What is the theoretical yield of a reaction if 25.0 grams of product were actually produced from a reaction that has a 88% yield? A) 352 B) 22.0 C) 28.4 D) ) 64) What is the limiting reactant for the following reaction given we have 3.4 moles of Ca(NO 3 ) 2 and 2.4 moles of Li 3 PO 4? Reaction: 3Ca(NO 3 ) 2 + 2Li 3 PO 4 6LiNO 3 + Ca 3 (PO 4 ) 2 A) Ca(NO 3 ) 2 B) Li 3 PO 4 C) Ca 3 (PO 4 ) 2 D) LiNO 3 64) 65) What is the excess reactant for the following reaction given we have 3.4 moles of Ca(NO 3 ) 2 and 2.4 moles of Li 3 PO 4? Reaction: 3Ca(NO 3 ) 2 + 2Li 3 PO 4 6LiNO 3 + Ca 3 (PO 4 ) 2 65) A) LiNO 3 B) Ca(NO 3 ) 2 C) Li 3 PO 4 D) Ca 3 (PO 4 ) 2 6

7 66) How many moles of lithium nitrate are theoretically produced if we start with 3.4 moles of Ca(NO 3 ) 2 and 2.4 moles of Li 3 PO 4? Reaction: 3Ca(NO 3 ) 2 + 2Li 3 PO 4 6LiNO 3 + Ca 3 (PO 4 ) 2 A) 1.1 B) 6.8 C) 7.2 D) ) 67) How many grams of calcium phosphate are theoretically produced if we start with 3.40 moles of Ca(NO 3 ) 2 and 2.40 moles of Li 3 PO 4? Reaction: 3Ca(NO 3 ) 2 + 2Li 3 PO 4 6LiNO 3 + Ca 3 (PO 4 ) 2 A) 248 B) 351 C) 1054 D) ) 68) How many grams of NO2 are theoretically produced if we start with 1.20 moles of S and 9.90 moles of HNO3? Reaction: S + 6HNO3 H2SO4 + 6NO2 + 2H2O A) 455 B) 331 C) 7.20 D) ) 69) What is the limiting reactant for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH) 2? Reaction: 2HCl + Ca(OH) 2 2H 2 O + CaCl 2 A) CaCl 2 B) Ca(OH) 2 C) H 2 O D) HCl 69) 70) What is the excess reactant for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH) 2? Reaction: 2HCl + Ca(OH) 2 2H 2 O + CaCl 2 A) Ca(OH) 2 B) H 2 O C) CaCl 2 D) HCl 70) 71) How many moles of calcium chloride are theoretically produced for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH) 2? Reaction: 2HCl + Ca(OH) 2 2H 2 O + CaCl 2 A) 1.4 B) 0.7 C) 1.0 D) ) 72) How many grams of water are theoretically produced for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH) 2? Reaction: 2HCl + Ca(OH) 2 2H 2 O + CaCl 2 A) 25.2 B) C) 50.4 D) ) 73) In order to determine the limiting reactant in a particular reaction, one must know each of the following EXCEPT A) the molar mass of each reactant present. B) the mass of each reactant present. C) the coefficient of each reactant in a balanced equation. D) the mass of each product formed. 73) 74) What is the limiting reactant for the reaction below given that you start with 2.50 grams C and 2.50 grams SiO2? Reaction: C + SiO2 SiC + O2 A) SiC B) SiO2 C) C D) O2 74) 7

8 75) What is the limiting reactant for the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O 2? A) O 2 B) Al 2 O 3 C) Al D) both Al and O 2 75) 76) What is the excess reactant for the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O 2? A) Al B) Al 2 O 3 C) O 2 D) both Al and O 2 76) 77) How many moles of aluminum oxide are produced according to the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O 2? A) B) C) D) ) 78) How many grams of aluminum oxide are produced according to the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O 2? A) B) 40.4 C) 18.9 D) ) 79) If 16.0 grams of aluminum oxide were actually produced, what is the percent yield of the reaction below given that you start with 10.0 g of Al and 19.0 grams of O 2? A) 84.7% B) 39.6% C) 75.0% D) 100% 79) 80) A sample of 8.5 g NH 3 on oxidation produces 4.5 g of NO. Calculate the percent yield. Reaction: 4 NH O 2 4 NO + 6 H 2 O A) 70% B) 30% C) 15 % D) 60% 80) 81) The reaction for the oxidation of NH 3 is given as: 4 NH O 2 4 NO + 6 H 2 O Under certain conditions the reaction will proceed at 29.8% yield of NO. How many grams of NH 3 must be made to react with excess oxygen to yield 70.5 g of NO? A) 134 B) 2.37 C) 21.0 D) ) 82) How many grams of the excess reactant are left over according to the reaction below given that you start with 10.0 g of Al and 19.0 grams of O 2? A) 8.90 B) 14.6 C) 10.1 D) ) 83) How many moles of NH 3 can be produced by the reaction of 2.00 g of N 2 with 3.00 g H 2? Reaction: N 2 (g) + 3 H 2 (g) 2 NH 3 (g) A) B) 1.00 C) D) ) 8

9 84) Calculate the maximum number of grams of NH 3 that can be produced by the reaction of 2.00 g of N 2 with 3.00 g H 2. Reaction: N 2 (g) + 3 H 2 (g) 2 NH 3 (g) A) B) 17.0 C) 4.00 D) ) 85) A 24.0 g sample of nitrogen gas reacts with an excess of hydrogen gas to give an actual yield of 3.85 g NH 3. What is the percent yield for this reaction? Reaction: N 2 (g) + 3 H 2 (g) 2 NH 3 (g) A) 13.2% B) 73.6% C) 26.4% D) 86.8% 85) 86) Which is the excess reactant in the following reaction given that you start with 15.5 g of Na2S and 12.1 g CuSO 4? Reaction: Na 2 S + CuSO 4 Na 2 SO 4 + CuS A) Na 2 SO 4 B) CuS C) Na 2 S D) CuSO 4 86) 87) Which is the limiting reactant in the following reaction given that you start with 15.5 g of Na 2 S and 12.1 g CuSO 4? Reaction: Na 2 S + CuSO 4 Na 2 SO 4 + CuS A) CuSO 4 B) CuS C) Na 2 SO 4 D) Na 2 S 87) 88) Which is the limiting reactant in the following reaction given that you start with 42.0 g of CO2 and 99.9 g KOH? Reaction: CO2 + 2KOH K2CO3 + H2O A) K2CO3 B) H2O C) KOH D) CO2 88) 89) What is the theoretical yield in grams of CuS for the following reaction given that you start with 15.5 g of Na 2 S and 12.1 g CuSO 4? Reaction: Na 2 S + CuSO 4 Na 2 SO 4 + CuS A) B) C) 7.25 D) ) 90) What is the percent yield of CuS for the following reaction given that you start with 15.5 g of Na 2 S and 12.1 g CuSO 4? The actual amount of CuS produced was 3.05 g. Reaction: Na 2 S + CuSO 4 Na 2 SO 4 + CuS A) 18.93% B) 16.1% C) 7.25% D) 42.1% 90) 91) How many grams of the excess reactant remain assuming the reaction goes to completion and that you start with 15.5 g of Na 2 S and 12.1 g CuSO 4? Reaction: Na 2 S + CuSO 4 Na 2 SO 4 + CuS A) 0.05 B) 9.58 C) 5.92 D) ) 9

10 92) Consider the reaction: 2 Al + 3Br2 2 AlBr3 Suppose a reaction vessel initially contains 5.0 mole Al and 6.0 mole Br2. What is in the reaction vessel once the reaction has occurred to the fullest extent possible? A) 2.0 mole Al; 3.0 mole Br2; 2.0 mole AlBr3 B) 0 mole Al; 0 mole Br2; 11.0 mole AlBr3 C) 0 mole Al; 1.0 mole Br2; 4.0 mole AlBr3 D) 1.0 mole Al; 0 mole Br2; 4.0 mole AlBr3 92) 93) The reaction of one mole of nitrogen gas with three moles of hydrogen gas releases 92 kj of thermal energy to the surroundings. Which of the following is TRUE? A) This reaction is exothermic. B) Complete reaction of two moles of nitrogen gas would release 184 kj of thermal energy in this reaction. C) This reaction has a negative enthalpy of reaction. D) All of the above are true. 93) 94) Consider the following reaction: 2 Mg + O2 2 MgO H rxn = kj Calculate the amount of heat (in kj) associated with complete reaction of 4 moles of Mg. A) kj B) kj C) kj D) kj 94) 95) Consider the following equation: CO + 2 H2 CH3OH H rxn = -128 kj Calculate the amount of heat (in kj) associated with complete reaction of 8.08 g H2. A) -256 kj B) -512 kj C) kj D) kj 95) 96) How many moles of water are needed to react with 2.2 moles of Li 2 O? Given: Li 2 O + H 2 O 2 LiOH A) 2.2 B) 1.5 C) 1.1 D) ) 97) How many grams of water are needed to react with 27.2 grams of Li 2 O? Given: Li 2 O + H 2 O 2 LiOH A) 1.51 B) C) 16.4 D) ) 98) If the theoretical yield of the reaction below corresponds to 99.2 g and the actual yield was 60.9 g, calculate the percent yield. Given: Li 2 O + H 2 O 2 LiOH A) 16.0 % B) 61.4 % C) 38.0 % D) 71.8 % 98) 99) If the theoretical yield of the reaction below corresponds to 25.3 g and the percent yield of the reaction is known to be reproducibly 81.1%, calculate the actual yield. Given: Li 2 O + H 2 O 2 LiOH A) 45.8 g B) 48.9 g C) 81.1 g D) 20.5 g 99) 100) Starting with 156 g Li 2 O and 33.3 g H 2 O, decide which reactant is present in limiting quantities. Given: Li 2 O + H 2 O 2 LiOH A) insufficient data B) lithium hydroxide C) lithium oxide D) water 100) 10